Good Morning! Take out your homework packet Turn to 17.4 practice (P = I x V) We will go over answers as a class

Wednesday, May 13, 2015 Learning Target: I can assess what I need to study before my test on Friday. Today: Go over answers to homework packet Turn in! Work time on Review Packet *Practice Test/Review tomorrow!!

Warm Up What is magnetic declination? Draw a sketch of the Earth: Where is the geographic south pole? Where is the magnetic south pole?

Work Time Goals: Tomorrow: Turn in Homework Packet Get majority of Review Packet finished Improve class test average! –we’re a team!  Tomorrow: Review packet should be done Practice test/assess where we are at!

Exit Question a. Your cell phone charger uses 8 amps of current when plugged into a 120 volt outlet. What is the power rating of the toaster in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does your charger use if you use it for 14 hours a month? d. The utility company charges $0.12 per kilowatt-hour. What does it cost you to use the charger for that month?

Warm Up At which point(s) (A, B, C, or D) could the SOUTH pole of a magnet be placed in order to make the rotor spin counter clockwise?

Warm Up Which way is the north pole in the electromagnet below? Which way will the north end of a needle on your compass point?

17.4 Generating Electricity Chapter 17 17.4 Generating Electricity

Generating Electricity Lots of heat energy is generated from coal, gas, and oil Most of the heat energy is “lost” as unusable energy

Generating Electricity Nonrenewable resources: not replaced as it is used (ex: coal, oil, natural gas) Renewable resources: a natural resource that can be replaced (ex: falling water, Sun, wind)

Electricity from Fossil Fuels Three major fossil fuels: coal, oil, natural gas wikipedia: fossil fuels Take a long time to form!

Better(?) Forms of Energy Nuclear Energy Wind Energy (renewable) Solar Energy (renewable) Hydroelectric [water] Energy (renewable) Geothermal Energy (renewable) Biomass Energy (renewable)

Electricity from Nuclear Energy Nuclear energy does not pollute the air like fossil fuel power plants do.

Electricity from Nuclear Energy Disadvantage = storage of nuclear waste Uranium fuel from the reactor stays dangerously radioactive for a long time.

Renewable: Wind Energy wikipedia California was the first U.S. state to build large wind farms. Wind farms can disturb natural habitats, and can perhaps scar a large area of scenery.

Renewable: Solar Energy The Sun’s energy is often called solar energy. A solar cell (also known as a photovoltaic cell) can convert solar energy to electricity.

Renewable: Hydroelectric Power Hoover Dam http://www.greeniacs.com/GreeniacsArticles/Energy/Hydroelectric-Power.html A hydroelectric (or hydropower) plant uses energy from falling water to generate electricity.

Renewable: Geothermal Energy Geothermal power plants use Earth’s internal heat energy, in the form of water or steam, to produce electricity. A geothermal heat pump system takes advantage of the relatively constant temperature of Earth’s shallow ground. http://www1.eere.energy.gov/geothermal/powerplants.html

Renewable: Biomass Energy Biomass is organic material from plants or animals. In waste-to-energy plants, renewable solid waste is burned to produce electricity, which also creates some air pollution.

Quick Check! List 3 fossil fuels. Are fossil fuels nonrenewable or renewable? EXPLAIN. List 3 renewable resources.

Power = current x voltage Electrical Power Electrical power: the rate at which electrical energy is changed into other forms of energy such as heat, sound, or light. Electrical power is measured in watts, just like mechanical power. Power = current x voltage P = I V

# of kilowatt-hours = # of kilowatts x hours Electrical Power Utility companies charge customers for the number of kilowatt-hours (kWh) used each month. A kilowatt-hour is a unit of energy, not power # of kilowatt-hours = # of kilowatts x hours

Electrical Power Example a. A toaster uses 12 amps of current when plugged into a 120 volt outlet. What is the power rating of the toaster in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the toaster use if you use it for 2.5 hours a month? d. The utility company charges $0.15 per kilowatt-hour. What does it cost you to use the toaster for that month?

Electrical Power Example a. A microwave uses 2 amps of current when plugged into a 80 volt outlet. What is the power rating of the microwave in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the microwave use if you use it for 8.2 hours a month? d. The utility company charges $0.25 per kilowatt-hour. What does it cost you to use the microwave for that month?

Electrical Power Example a. A computer uses 5 amps of current when plugged into a 120 volt outlet. What is the power rating of the computer in watts? b. What is the power rating in kilowatts? c. How many kilowatt-hours does the computer use if you use it for 28 hours a month? d. The utility company charges $0.12 per kilowatt-hour. What does it cost you to use the computer for that month?